Experimental reorganization in the alar plate of the clawed toad, Xenopus laevis. I. Quantitative and qualitative effects of embryonic otocyst extirpation.
The area octavolateralis and the lateral line projections were examined in larval and postmetamorphic clawed toads, which had one otic vesicle removed at embryonic stage 38 (ref. 20). Premetamorphic tadpoles show a smaller octavolateral area on the operated side as compared to the contralateral control side. This area is in postmetamorphic toadlets significantly reduced as compared to the control side. The largest cells of the magnocellular vestibular nucleus show no significant difference in size to the contralateral side. A dorsolateral auditory nucleus develops prior to metamorphosis and shows in tadpoles no differences in cell size. Cell of this nucleus are in small toads only about 60% the size of cells in the contralateral nucleus. Countings in toadlets indicate a reduction of 40% in cell number on the operated side. Both tadpoles and small toads show virtually no differences in the lateral line projection compared to controls. Only rare collaterals of lateral line fibres can be traced into the neighbouring vestibular and auditory nuclei. The data show no preferential innervation of inner ear afferent deprived auditory and vestibular nuclei by lateral line afferents. In contrast, some collaterals of somatosensory fibres reach into the area deprived of octaval afferents.
Fritzsch
B
B
University of Bielefeld, Faculty of Biology, F.R.G.
D000818:Animals; D007758:Ear, Inner / Q000166:cytology / Q000196:embryology*; D009473:Neuronal Plasticity; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology*